Effects of gender and altitude on short-term heart rate variability in children/Cocuklarda rakim ve cinsiyetin kalp atim hizi degiskenligi uzerine etkileri.ABSTRACT Objective: We aimed to study short-term heart rate variability Heart rate variability (HRV) is a measure of variations in the heart rate. It is usually calculated by analysing the time series of beat-to-beat intervals from ECG or arterial pressure tracings. (HRV HRV Croatia (ISO Country code) HRV Heart Rate Variability HRV Human Rhinovirus HRV Heat Recovery Ventilator HRV High Resolution Visible HRV Haute Resolution Visible HRV Hypersonic Research Vehicle HRV Hercules Recovery Vehicle ) in 113 apparently healthy children permanent residents of moderate altitudes, the effects of gender and altitude. Methods: Children were assigned into 3 groups according with altitude of residence: Group 1--1650 m/a/s/l (n=38), Group 2--1740 m/a/s/l (n=36) and Group 3--2030 m/a/s/l (n=39). All children underwent short-term electrocardiographic electrocardiographic emanating from or pertaining to electrocardiography. electrocardiographic monitoring maintenance of a more or less continuous surveillance of a patient's cardiac status by means of electrocardiography. recordings with spectral analysis Spectral analysis may refer to:
see analysis of variance. ANOVA Analysis of variance, see there analysis. Results: Heart rate variability analysis showed significant increase in SDNN SDNN Standard Deviation of Normal-to-Normal Intervals , high frequency and total powers in parallel with increase of the altitude of residence (p<0.0001, p<0.03 and p<0.01, respectively). The magnitude of the HRV response to posture did not differ between groups except index of sympathetic modulation, LFNU, which rose to a significantly lesser degree (F=3.45, p<0.03) in Group 3, as compared with Group 1 and 2. Girls had lower HRV as compared with boys. Conclusion: Thus, in apparently healthy children, residents of moderate altitudes, increase in altitude levels is accompanied by higher overall variability and parasympathetic parasympathetic /para·sym·pa·thet·ic/ (-sim?pah-thet´ik) see under system. par·a·sym·pa·thet·ic adj. Of, relating to, or affecting the parasympathetic nervous system. modulation of the sinus node sinus node n. See sinoatrial node. sinus node Sinoatrial node, see there, SA node and lower sympathetic response to posture. Heart rate variability in children, residents of moderate altitudes is also dependent of gender, resembling similar relationship in inhabitants
The game is based loosely on the concepts from SameGame. of sea level. (Anadolu Kardiyol Derg 2006; 6: 335-9) Key words: Heart rate variability, children, altitude, gender, posture OZET Amac: Bu califlmada, orta rakimda devamli yaflayan 113 saglikli cocukta cinsiyet ve yoksekligin kalp atim hizi degiflkenligi (KAHD KAHD Kansas Animal Health Department ) uzerine etkilerini arafltirmayi amacladik. Yontemler: Ikamet edilen deniz seviyesi yuksekligine gore tum cocuklar 3 gruba ayrildi: Grup 1--1650 m/d/s (n=38), Grup 2--1740 m/d/s (n=36) ve Grup 3--2030 m/d/s (n=39). Tum bireylerde yatarken ve ayakta kisa sureli elektrokardiyogram cekildi ve KAHD spektral analizi yapildi. Istatistiksel analiz cok yonlu ANOVA testi ile uygulandi. Bulgular: Yapilan KAHD analizi, SDNN, yuksek frekansli ve total guclerin deniz seviyesi yuksekligi ile paralel olarak arttiklanni (sirarasi ile p<0.0001, p<0.03 ve p<0.01) gostermistir. Vucut durusunun degisikligine KAHD'nin cevabi incelendiginde gruplar arasi belirgin bir fark bulunmadi. Sadece LFNU- sempatik modulasyon indeksinin artifli Grup 3'te diger gruplara (Grup 1 ve 2) gore anlamli olarak daha dufluk seviyede bulundu (F=3.45, p<0.03). Kizlarda KAHD erkeklere gore daha dufluktu. Sonuc: Orta rakimda devamli yaflayan saglikli cocukta, deniz seviyesi yuksekligin artifli KAHD ve sinus dugumunun parasempatik modulasyonunun artmasina ve durufl deflikligine sempatik cevabinin azalmasina neden olmaktadir. Bu cocuklarda, deniz seviyesinde yaflayan bireylerin iliskilerine benzer olarak KAHD cinsiyete bagli bulunmufltur. (Anadolu Kardiyol Derg 2006; 6: 335-9) Anahtar kelimeler: Kalp atim hizi degiskenligi, cocuk, rakim, cinsiyet, durus Introduction Heart rate variability (HRV), representing the beat-to-beat variation in cardiac cycle cardiac cycle n. A complete beat of the heart, including systole and diastole and the intervals between, beginning with any event in the heart's action to the moment when that same event is repeated. , is thought to reflect autonomic autonomic /au·to·nom·ic/ (aw?to-nom´ik) not subject to voluntary control. See under system. au·to·nom·ic adj. 1. Functionally independent; not under voluntary control. modulation of the sinus node, namely parasympathetic and sympathetic modulations, and sympathovagal interaction when analyzed by spectral techniques (1, 26, 29, 36, 37). Heart rate variability is reduced in children with cardiac diseases and it has been recognized to correlate with the functional deterioration and life-threatening arrhythmias in children with congenital heart anomalies before and after their surgical correction (7, 12, 18, 19, 25). High altitudes are known to modify autonomic responses with higher parasympathetic activity in native inhabitants of highlands (5, 23, 27, 42) and enhanced sympathetic modulation during acute ascent in low lands inhabitants (28, 33). At the same time, high altitudes through chronic exposure to hypoxia hypoxia Condition in which tissues are starved of oxygen. The extreme is anoxia (absence of oxygen). There are four types: hypoxemic, from low blood oxygen content (e.g., in altitude sickness); anemic, from low blood oxygen-carrying capacity (e.g. and other environmental factors (29, 34) could increase the incidence of congenital heart diseases congenital heart disease, any defect in the heart present at birth. There is evidence that some congenital heart defects are inherited, but the cause of most cases is unknown. , especially patent ductus arteriozus, atrial septal defect Atrial Septal Defect Definition An atrial septal defect is an abnormal opening in the wall separating the left and right upper chambers (atria) of the heart. , tetralogy of Fallot Tetralogy of Fallot Definition Tetralogy of Fallot is a common syndrome of congenital heart defects. Description The heart is two pumps in one. in children permanent residents of moderate and high altitudes (4, 8, 14, 22). Notwithstanding, the physiological and clinical significance of HRV and autonomic modulation of heart rate in children residing at moderate and high altitudes, healthy or those with cardiac diseases are not studied broadly. We aimed to investigate short-term heart rate variability in children permanent inhabitants of moderate altitudes, the effects of gender, altitude and response to posture. Material and Methods Overall 113 apparently healthy children (58 girls and 55 boys, age range 9-10 years), of 150 permanent residents of three counties situated at 1650, 1740, and 2030 meters above the sea level underwent general health examinations with eligible electrocardiographic recordings, were included into the study. Children were assigned into three groups according with the altitude of residence - Group 1 - 1650 m above the sea level (n=38), Group 2--1740 m above the sea level (n=36) and Group 3--2030 m (n=39) above the sea level. All children underwent general health evaluation and shortterm ECG ECG electrocardiogram. ECG abbr. 1. electrocardiogram 2. electrocardiograph ECG Also called an electrocardiogram, it records the electrical activity of the heart. recordings at rest and during posture in the ambulatory polyclinics situated at the same level of permanent residency Permanent residency refers to a person's visa status: the person is allowed to reside indefinitely within a country despite not having citizenship. A person with such status is known as a permanent resident. of children (1650, 1740 and 2030 meters above the sea level). ECG recordings were further analyzed by spectral analysis of HRV (fast Fourier transformation) with specially developed software according with standard requirements for HRV processing and evaluation of short-term recordings (36). The following measures of HRV were calculated: standard deviation In statistics, the average amount a number varies from the average number in a series of numbers. (statistics) standard deviation - (SD) A measure of the range of values in a set of numbers. of RR intervals (SDNN), low frequency (LF. 0.04-0.15 Hz) and high frequency (HF, 0.15-0.40 Hz) spectral powers, total power under the spectral curve (TP, 0.0-0.40 Hz), LF/HF ratio and the LF normalized power (LFNU) calculated as the LFNU=(absolute LF power /TP)x100 . Statistical analysis was performed using SPSS A statistical package from SPSS, Inc., Chicago (www.spss.com) that runs on PCs, most mainframes and minis and is used extensively in marketing research. It provides over 50 statistical processes, including regression analysis, correlation and analysis of variance. for Windows 10.0, Chicago IL, USA software by Kolmogorov-Smirnov test In statistics, the Kolmogorov–Smirnov test (often called the K-S test) is used to determine whether two underlying one-dimensional probability distributions differ, or whether an underlying probability distribution differs from a hypothesized distribution, in either for assessment of normality of data distribution, unpaired t test for comparison of gender specified groups, paired Students t tests for evaluation of the intra-group changes during posture, ANOVA for assessment of differences for altitude specified groups and multivariate analysis multivariate analysis, n a statistical approach used to evaluate multiple variables. multivariate analysis, n a set of techniques used when variation in several variables has to be studied simultaneously. of variance (MANOVA MANOVA Multivariate Analysis of the Variance ) to assess the relationship of HRV changes with altitude, gender and posture. Results Heart rate variability analysis showed significant increase in SDNN, HF and TP in parallel with increase of the altitude of residence (p<0.0001, p<0.03 and p<0.01, respectively) of children (Table 1). These differences in HRV between groups in regard to altitude were also preserved in the posture position (p<0.04 for SDNN, p<0.02 for Log HF and p<0.05 for Log TP). Evaluation of the HRV changes during posture (Table 1 and Fig. 1) according with altitude levels revealed uniform significant all p<0.0001) reduction of mean RR interval in all groups and marked decrease in SDNN value in Groups 2 and 3 (p<0.01 and p<0.001, respectively). Children of Group 1 and 2 had an uniform reduction in Log HF (p<0.001 and p<0.001, respectively), with concomitant increase in LF/ HF ratio (p<0.001 and p<0.01) and LFNU p<0.001 for all), while changes in the former parameters in the Group 3 did not reach statistical significance. [FIGURE 1 OMITTED] Multivariate analysis (Fig. 1) of the response to posture according with altitude of residence showed no difference in the magnitude of HRV changes between groups except LFNU, index of sympathetic modulation of heart rate, which rose to a significantly lesser degree (F=3.45, p<0.03) in Group 3, as compared with Group 1 and 2. Gender-related differences in HRV (Table 2) were characterized by shorter RR interval (p<0.02), lower SDNN (p<0.01), Log LF p<0.016) and Log TP (p<0.057) in girls as compared with boys. Assessment of the gender-specific response to posture (Fig. 2) showed that boys had more profound reduction in SDNN F=5.42, p<0.02) and Log TP (F=3.32, p<0.07). The main feature was different response in Log LF in girls as compared with boys, which increased (p<0.01) during posture changes in girls and reduced in boys (F=6.17, p<0.01). When these responses were analyzed with adjustment for altitude of residence, the similar pattern was observed. [FIGURE 2 OMITTED] Discussion Our study demonstrated, that in apparently healthy children permanent inhabitants of moderate altitudes increase in levels of altitude of residence is accompanied by higher overall variability (SDNN and TP) and parasympathetic modulation (high frequency variability) of the sinus node with lower sympathetic (LFNU) response to posture, as assessed by short-term HRV analysis. Gender-related differences in children residing at middle altitudes are characterized by lesser values of HRV in girls in comparison with boys and different responses to posture of overall HRV index and LF component. Heart rate variability analysis studies in children showed that HRV gradually increases from neonatal period Noun 1. neonatal period - the first 28 days of life time of life - a period of time during which a person is normally in a particular life state to adolescent period accordingly with reduction of heart rate (30). The autonomic maturation is especially should be regarded to HF component of HRV with its fairly discernible peak in neonates and its further increase in adolescents due to increase in myelination myelination /my·elin·a·tion/ (mi?e-lin-a´shun) myelinization. my·e·li·na·tion or my·e·li·ni·za·tion n. The acquisition, development, or formation of a myelin sheath around a nerve fiber. of vagal vagal /va·gal/ (va´gal) pertaining to the vagus nerve. va·gal adj. Of or relating to the vagus nerve. vagal pertaining to the vagus nerve. fibers and decrease in heart rate (9). The lower frequency of LF peak in children was explained by lower transmission rate of the signal and immature autonomic nervous system autonomic nervous system: see nervous system. autonomic nervous system Part of the nervous system that is not under conscious control and that regulates the internal organs. It includes the sympathetic, parasympathetic, and enteric nervous systems. (15). The age-related increase in short and medium-term HRV and changes in autonomic nervous system continues up to age of 8-10 (2, 3), after what only the changes in long-term HRV (SDANN) were noticed (32, 37). We included in the study only the children/preadolescents at age of 9-10 years, assuming the stabilization in sympathetic and parasympathetic limbs reactivity (32). Our findings on gradual increase in HF with increase in altitude in children inhabitants of moderate altitudes are in concert with previous findings on increase of parasympathetic modulation of heart rate with increase of altitude reported in adults (5, 27). The increase in parasympathetic modulation of heart rate has been reported also in young Tibetians (42) and in newborns at high altitudes (23). These changes in autonomic regulation in native inhabitants of high altitudes were attributed to effects of hypoxia and hypobaria (31). Since hypoxia is also observed at middle altitudes (40) we can assume that they also could influence the altitude differences of HRV in our children. We also showed in multivariate analysis that children residing at higher altitudes had lower response of sympathetic modulation of heart rate as compared with those living at lower altitudes. The lower response of sympathetic modulation of HR at higher altitudes may be also attributed to inhibiting effects of hypoxia on ?-adrenergic responsiveness (16, 17, 20). Gender related differences have been reported (11) for higher HRV in boys than in girls of 3-15 years old, though others (6, 35) described no differences at all. Our findings on gender-related changes in HRV of children inhabitants of moderate altitudes are in concert with previous studies on HRV extracted from 24-hour ECG recordings (10, 13, 37, 38). Silvetti et al. (29) found higher SDNN for boys and no differences in parasympathetic (pNN50, RMSSD) modulation between genders. Similarly, we showed that SDNN was markedly lower in girls that in boys, however we also found differences in slow fluctuations (LF) and accordingly TP, which were lower in girls than in boys, inhabitants of moderate altitudes. These differences in LF component have already been described for adult women as compared with middle-aged men by Huikuri et al (13). Faulkner et al. (10) attributed the differences in overall HRV in children of this age to the start of secondary sexual characteristics Noun 1. secondary sexual characteristic - the genetically determined sex characteristics that are not functionally necessary for reproduction (pitch of the voice and body hair and musculature) secondary sex character, secondary sex characteristic in circadian circadian /cir·ca·di·an/ (ser-ka´de-an) denoting a 24-hour period; see under rhythm. cir·ca·di·an adj. Relating to biological variations or rhythms with a cycle of about 24 hours. patterns. Though it is not well explained, similar can be speculated for gender differences in HRV in children inhabitants of moderate altitudes (35, 41). The main limitation of our study is the absence of control group of children permanently residing at sea level (50-100 m above the sea level) and narrow age limits. Further studies should be addressed to elucidate effects of altitudes on heart rate variability and autonomic modulation in children residing at high altitudes, as well the relationship of HRV and cardiovascular diseases Cardiovascular disease Disease that affects the heart and blood vessels. Mentioned in: Lipoproteins Test cardiovascular disease in residents of moderate and high altitudes. Conclusion Thus, in apparently healthy children, residents of moderate altitudes, increase in altitude levels is accompanied by higher overall variability and parasympathetic modulation of the sinus node and lower sympathetic response to posture. HRV in children, residents of moderate altitudes is also dependent of gender, resembling similar relationship in inhabitants of sea level. Address for Correspondence: Ainash Sharshenova, MD, PhD, Scientific and Production Center of Preventive Medicine preventive medicine, branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. , 34 Baitik Baatyr Str. Bishkek, 720005, Kyrgyzstan Fax: +996 312 544573 E-mail: asharshenova@yahoo.com Note: The work was presented at thee joint European Society of Cardiology The European Society of Cardiology (ESC) represents more than 50,000 cardiology professionals across Europe and the Mediterranean. Its mission is to reduce the impact of cardiovascular disease in Europe. and World Heart Federation Congress of Cardioogy--22--66 September 2006, Barcelona, Spain References (1.) Akselrod, S, Gordon, D, Ubel, FA, Shannon, DC, Berger, AC, Cohen cohen or kohen (Hebrew: “priest”) Jewish priest descended from Zadok (a descendant of Aaron), priest at the First Temple of Jerusalem. The biblical priesthood was hereditary and male. , RJ. Power spectrum analysis of heart rate fluctuation: a quantitative probe of beat-to-beat cardiovascular control. Science 1981; 213: 220-2. (2.) Alkon A, Goldstein LH, Smider N, Essex MJ, Kupfer DJ, Boyce WT. Developmental and contextual influences on autonomic reactivity in young children. Dev Psychobiol 2003; 42: 64-78. (3.) Allen M, Matthews K. Hemodynamic responses hemodynamic response Cardiology Response of the circulatory system to stimuli such as exercise, emotional stress, etc to laboratory stressors in children and adolescents: The influences of age, race, and gender. Psychophysiology psychophysiology /psy·cho·phys·i·ol·o·gy/ (-fiz?e-ol´ah-je) physiologic psychology. psy·cho·phys·i·ol·o·gy n. The study of correlations between the mind, behavior, and bodily mechanisms. 1997; 34: 329-39. (4.) Alzamora Castro V, Battilana G, Abugattas R, Sialer S. Patent ductus arteriosus Patent Ductus Arteriosus Definition Patent ductus arteriosus (PDA) is a heart defect that occurs when the ductus arteriosus (the temporary fetal blood vessel that connects the aorta and the pulmonary artery) does not close at birth. and high altitude. Am J Cardiol 1960; 5: 761-3. (5.) Bernardi L, Passino C, Spadacini G, Calciati A, Robergs R, Greene R, et al. Cardiovascular autonomic modulation and activity of carotid carotid /ca·rot·id/ (kah-rot´id) pertaining to the carotid artery, the principal artery of the neck. ca·rot·id n. baroreceptors at altitude. Clin Sci (Lond) 1998; 95: 565-73. (6.) Brunetto AF, Roseguini BT, Silva BM, Hirai DM, Guedes DP. Effects of gender and aerobic fitness aerobic fitness Clinical medicine A value obtained from exercise testing, which is expressed as either VO 2 peak–O2 consumption at peak exercise, or Wpeak on cardiac autonomic responses to head-up tilt in healthy adolescents. Pediatr Cardiol 2005; 26: 418-24. (7.) Butera G, Bonnet D, Sidi D, Kachaner J, Chessa M, Bossone E, et al. Patients operated for tetralogy of Fallot and with non-sustained ventricular tachycardia Ventricular Tachycardia Definition Ventricular tachycardia (V-tach) is a rapid heart beat that originates in one of the lower chambers (the ventricles) of the heart. have reduced heart rate variability. Herz 2004; 29: 304-9. (8.) Dalen, JE, Bruce, RA, Cobb, LA. Interaction of chronic hypoxia of moderate altitude on pulmonary hypertension Pulmonary Hypertension Definition Pulmonary hypertension is a rare lung disorder characterized by increased pressure in the pulmonary artery. The pulmonary artery carries oxygen-poor blood from the lower chamber on the right side of the heart (right complicating defect of the atrial atrial /atri·al/ (a´tre-al) pertaining to an atrium. a·tri·al adj. Of or relating to an atrium. Atrial Having to do with the upper chambers of the heart. septum septum /sep·tum/ (sep´tum) pl. sep´ta [L.] a dividing wall or partition. alveolar septum interalveolar s. . N Engl J Med 1962; 266: 272-7. (9.) Doussard-Roosevelt JA, McClenny BD, Porges SW. Neonatal cardiac vagal tone and school-age developmental outcome in very low birth weight infants. Dev Psychobiol 2001; 38: 56-66. (10.) Faulkner MS, Hathaway D, Tolley B. Cardiovascular autonomic function in healthy adolescents. Heart Lung 2003; 32: 10-22. (11.) Goto M, Nagashima M, Baba R. Analysis of heart rate variability demonstrates effects of development on vagal modulation of heart rate in healthy children. J Pediatr 1997; 130: 725-9. (12.) Heragu NP, Scott WA. Heart rate variability in healthy children and in those with CHD CHD coronary heart disease. ChD abbr. Latin Chirurgiae Doctor (Doctor of Surgery) CHD, n.pr See disease, coronary heart. CHD canine hip dysplasia. before and after operation. Am J Cardiol 1999; 83: 1654-7. (13.) Huikuri HV, Pikkujamsa SM, Airaksinen KE, Ikaheimo MJ, Rantala AO, Kauma H, et al. Sex-related differences in autonomic modulation of heart rate in middle-aged subjects. Circulation 1996; 94: 122-5. (14.) Khoury GH, Hawes CR. Atrial septal defect associated with pulmonary hypertension in children living at high altitude. J Pediatr 1967; 70: 432-5. (15.) Longin E, Schaible T, Lenz T, Konig S. Short-term heart rate variability in healthy neonates: normative data and physiological observations. Early Hum Dev 2005; 81: 663-71. (16.) Maher JT, Deniiston JC, Wolfe DL, Cymerman A. Mechanism of the attenuated Attenuated Alive but weakened; an attenuated microorganism can no longer produce disease. Mentioned in: Tuberculin Skin Test attenuated having undergone a process of attenuation. cardiac response to beta-adrenergic stimulation in chronic hypoxia. J Appl Physiol 1978; 44: 647-51. (17.) Maher JT, Manchanda SC, Cymerman A, Wolfe DJ, Hartley LH. Cardiovascular responsiveness to b-adrenergic stimulation and blockade in chronic hypoxia. Am J Physiol 1975; 228: 477-81. (18.) Massin, M, Derkenne, B, von Bernuth, G. Heart rate behavior in children with atrial septal defect. Cardiology cardiology Medical specialty dealing with heart diseases and disorders. It began with the 1749 publication by Jean Baptiste de Sénac of contemporary knowledge of the heart. Diagnostic methods improved in the 19th century, and in 1905 the electrocardiograph was invented. 1988; 90: 269 -73. (19.) Massin, M, von Bernuth, G. Clinical and haemodynamic correlates of heart rate variability in children with congenital heart disease. Eur J Pediatr 1998; 157: 967-71. (20.) Mazzeo RS, Bender PR, Brooks GA. Arterial catecholamine catecholamine (kăt'əkôl`əmēn), any of several compounds occurring naturally in the body that serve as hormones or as neutrotransmitters in the sympathetic nervous system. responses during exercise with acute and chronic high-altitude exposure. Am J Physiol 1991; 261 (Endocrinol. Metab): E419-24. (21.) McLeod KA, Hillis WS, Houston AB, Wilson N, Trainer A, Neilson J, et al. Reduced heart rate variability following repair of tetralogy of Fallot. Heart 1999; 81: 656-60. (22.) Miao CY, Zuberbuhler JS, Zuberbuhler JR. Prevalence of congenital cardiac anomalies at high altitude. J Am Coll Cardiol 1998; 12: 224-8. (23.) Mortola, JP, Leon-Velarde, F, Aguero, L, Frappell, PB. Heart rate variability in 1-day-old infants born at 4330 m altitude. Clin Sci (Lond) 1999; 96: 147-53. (24.) Niermeyer S. Cardiopulmonary cardiopulmonary /car·dio·pul·mo·nary/ (kahr?de-o-pool´mah-nar-e) pertaining to the heart and lungs. car·di·o·pul·mo·nar·y adj. Of, relating to, or involving both the heart and the lungs. transition in the high altitude infant. High Altitude Med & Biol 2003; 4: 225-39. (25.) Ohuchi H, Suzuki H, Toyohara K, Tatsumi K, Ono Y, Arakaki Y, et al. Abnormal cardiac autonomic nervous activity after right ventricular outflow tract A ventricular outflow tract is a portion of either the left or right ventricle of the human heart through which blood passes in order to enter the great arteries. The right outflow tract is an infundibular extension of the ventricular cavity, which connects to the pulmonary reconstruction. Circulation 2000; 102: 2732-8. (26.) Pagani M, Lombardi F, Guzzetti S, Rimoldi O, Furlan R, Pizzinelli P, et al. Power spectral analysis of heart rate and arterial pressure Noun 1. arterial pressure - the pressure of the circulating blood on the arteries; "arterial pressure is the product of cardiac output and vascular resistance" variabilities as a marker of sympathovagal interactions in man and conscious dog. Circ Res 1986; 59: 178-93. (27.) Passino C, Bernardi L, Spadacini G, Calciati A, Robergs R, Anand I, et al. Autonomic regulation of heart rate and peripheral circulation: comparison of high altitude and sea level residents. Clin Sci (Lond) 1996; 91 Suppl: 81-3. (28.) Perini R, Milesi S, Biancardi L, Veicsteinas A. Effects of high altitude acclimatization acclimatization Any of numerous gradual, long-term responses of an individual organism to changes in its environment. The responses are more or less habitual and reversible should conditions revert to an earlier state. on heart rate variability in resting humans. Eur J Appl Physiol Occup Physiol 1996; 73: 521-8. (29.) Pomeranz B, Macaulay RJ, Caudill MA, Kutz I, Adam D, Gordon D, et al. Assessment of autonomic function in humans by heart rate spectral analysis. Am J Physiol 1985; 248: H151-3. (30.) Sahni R, Schulze KF, Kashyap S, Ohira-Kist K, Fifer WP, Myers MM. Maturational changes in heart rate and heart rate variability in low birth weight infants. Dev Psychobiol 2000; 37: 73-81. (31.) Saito S, Tanobe K, Yamada M, Nishihara F. Relationship between arterial oxygen saturation oxygen saturation sO2 The O2 concentration of blood expressed as a ratio of its total O2-carrying capacity; the OS is a measure of the utilization of O2 transport capacity; sO2 and heart rate variability at high altitudes. Am J Emerg Med 2005; 23: 8-12. (32.) Salomon K, Matthews K, Allen M. Patterns of sympathetic and parasympathetic reactivity in a sample of children and adolescents. Psychophysiology 2000; 37: 842-9. (33.) Sevre K, Bendz B, Hanko E, Nakstad AR, Hauge A, Kasin JI, et al. Reduced autonomic activity during stepwise stepwise incremental; additional information is added at each step. stepwise multiple regression used when a large number of possible explanatory variables are available and there is difficulty interpreting the partial regression exposure to high altitude. Acta Physiol Scand 2001; 173: 409-17. (34.) Silvetti MS, Drago F, Ragonese P. Heart rate variability in healthy children and adolescents is partially related to age and gender. Int J Cardiol 2001; 81: 169-74. (35.) Tanaka H, Borres M, Thulesius O, Tamai H, Ericson MO, Lindblad LE. Blood pressure and cardiovascular autonomic function in healthy children and adolescents. J Pediatr 2006; 137: 63-7. (36.) Task Force of the European Society of Cardiology and the North American North American named after North America. North American blastomycosis see North American blastomycosis. North American cattle tick see boophilusannulatus. Society of Pacing and Electrophysiology electrophysiology /elec·tro·phys·i·ol·o·gy/ (-fiz?e-ol´ah-je) 1. the study of the mechanisms of production of electrical phenomena, particularly in the nervous system, and their consequences in the living organism. 2. . Heart rate variability: standards of measurement, physiological interpretation and clinical use. Circulation 1996; 93: 1043-65. (37.) Tulppo MP, Kiviniemi AM, Hautala AJ, Kallio M, Seppanen T, Makikallio TH, et al. Physiological background of the loss of fractal heart rate dynamics. Circulation 2005; 112: 314-9. (38.) Umetani K, Singer DH, McCraty R, Atkinson M. Twenty-four hour time domain heart rate variability and heart rate: relations to age and gender over nine decades. J Am Coll Cardiol 1998; 31: 593-601. (39.) Vargas PE, Spielvogel H. Chronic mountain sickness chronic mountain sickness n. Altitude sickness that occurs despite acclimatization to high altitudes, characterized by high levels of circulating red blood cells, hypoxemia, and reduced mental and physical capacity. Also called Monge's disease. , optimal hemoglobin hemoglobin (hē`məglō'bĭn), respiratory protein found in the red blood cells (erythrocytes) of all vertebrates and some invertebrates. , and heart disease. High Alt Med Biol 2006; 7: 138-49. (40.) Veglio M, Maule S, Cametti G, Cogo A, Lussiana L, Madrigale G, et al. The effects of exposure to moderate altitude on cardiovascular autonomic function in normal subjects. Clin Auton Res 1999; 9: 123-7. (41.) Wu T, Wang X, Wei C, Cheng H, Wang X, Li Y, et al. Hemoglobin levels in Qinghai-Tibet: different effects of gender for Tibetans vs. Han. J Appl Physiol 2005; 98: 598 - 604. (42.) Zhuang J, Zhu H, Zhou Z. Reserved higher vagal tone under acute hypoxia in Tibetan adolescents with long-term migration to sea level. Jpn J Physiol 2002; 52: 51-6. Ainash A. Sharshenova, Elvira J. Majikova, Omor T. Kasimov, Gulmira Kudaiberdieva Scientific and Production Center of Preventive Medicine, Bishkek, Kyrgyzstan
Table 1. HRV parameters in healthy children in supine and posture
changes according with the altitude of residence
Group 1 Group 2
1650m 1740 m
(n=38) (n=36)
RR, ms
Supine 823.3 [+ or -] 75.6 812.9 [+ or -] 110.3 *
Posture 708.8 [+ or -] 78.5 ### 695.1 [+ or -] 71.9 ###
SDNN, ms
Supine 55.7 [+ or -] 16.5 *** 59.0 [+ or -] 20.1 **
Posture 50.9 [+ or -] 17.6 50.6 [+ or -] 13.6 #
Log LF
Supine 2.30 [+ or -] 0.35 * 2.40 [+ or -] 0.41
Posture 2.35 [+ or -] 0.37 2.45 [+ or -] 0.35
Log HF
Supine 2.44 [+ or -] 0.27 * 2.51 [+ or -] 0.29
Posture 2.20 [+ or -] 0.38 ## * 2.31 [+ or -] 0.39 ##
Log TP
Supine 2.71 [+ or -] 0.25 ** 2.80 [+ or -] 0.29
Posture 2.62 [+ or -] 0.33 * 2.73 [+ or -] 0.32
LF/HF ratio
Supine 1.02 [+ or -] 0.95 1.11 [+ or -] 1.08
Posture 1.84 [+ or -] 1.22 ## 2.08 [+ or -] 2.3 #
LFNU, %
Supine 42.9 [+ or -] 18.2 44.3 [+ or -] 18.7
Posture 57.9 [+ or -] 18.0 ## 56.7 [+ or -] 19.6 ##
Group 3
2030 m
(n=39) F p
RR, ms
Supine 865.1 [+ or -] 78.9 3.6 0.03
Posture 722.9 [+ or -] 67.3 ### 1.3 NS
SDNN, ms
Supine 74.6 [+ or -] 23.8 9.2 0.0001
Posture 59.9 [+ or -] 22.1 ## 3.2 0.04
Log LF
Supine 2.52 [+ or -] 0.39 0.72 NS
Posture 2.43 [+ or -] 0.38 2.9 0.054
Log HF
Supine 2.61 [+ or -] 0.29 3.3 0.03
Posture 2.46 [+ or -] 0.45 3.9 0.02
Log TP
Supine 2.90 [+ or -] 0.28 4.3 0.01
Posture 2.80 [+ or -] 0.34 3.02 0.053
LF/HF ratio
Supine 1.06 [+ or -] 0.75 0.08 NS
Posture 1.56 [+ or -] 1.80 0.76 NS
LFNU, %
Supine 45.8 [+ or -] 16.9 0.24 NS
Posture 48.3 [+ or -] 22.2 2.6 0.07
*--p<0,05, **--p<0,01, ***--p<0,0001 Scheffe F test differences are
significant as compared with altitude of residence at 2030 m above the
sea level
#--p<0,01, ##--p<0,001, ###--p<0,0001 Student paired t test differences
are significant as compared with supine position
HF--frequency power, HRV--heart rate variability, LF--low frequency
power, LFNU--LF power expressed in normalized units,
NS--nonsignificant, SDNN--standard deviation of the normal-to-normal RR
intervals duration, TP--total power under the spectral curve
Table 2. Gender related differences in HRV of healthy children,
residents of moderate altitudes
Boys Girls
Parameters (n=38) (n=36)
RR, ms
Supine 854.5 [+ or -] 95.3 816.1 [+ or -] 84.1
Posture 722.5 [+ or -] 81.4 *** 697.1 [+ or -] 62.4 ***
SDNN, ms
Supine 68.4 [+ or -] 24.5 58.1 [+ or -] 17.7
Posture 54.5 [+ or -] 19.7 *** 53.4 [+ or -] 17.5
Log LF
Supine 2.50 [+ or -] 0.35 2.32 [+ or -] 0.41
Posture 2.40 [+ or -] 0.37 2.42 [+ or -] 0.36 *
Log HF
Supine 2.55 [+ or -] 0.33 2.49 [+ or -] 0.24
Posture 2.33 [+ or -] 0.47 ** 2.33 [+ or -] 0.36 **
Log TP
Supine 2.85 [+ or -] 0.29 2.75 [+ or -] 0.27
Posture 2.72 [+ or -] 0.37 ** 2.73 [+ or -] 0.3
LF/HF, ratio
Supine 1.19 [+ or -] 1.02 0.93 [+ or -] 0.81
Posture 1.78 [+ or -] 1.73 * 1.87 [+ or -] 1.91 **
LFNU, %
Supine 47.4 [+ or -] 17.1 41.4 [+ or -] 18.1
Posture 53.3 [+ or -] 20.5 55.1 [+ or -] 20.3 ***
Parameters p
RR, ms
Supine 0.02
Posture NS
SDNN, ms
Supine 0.01
Posture NS
Log LF
Supine 0.016
Posture NS
Log HF
Supine NS
Posture NS
Log TP
Supine 0.057
Posture NS
LF/HF, ratio
Supine NS
Posture NS
LFNU, %
Supine NS
Posture NS
*-p<0.01, **-p<0.001, ***-p<0.0001 Student paired t test differences
are significant as compared with supine position
HF--frequency power, HRV--heart rate variability, LF--low frequency
power, LFNU--LF power expressed in normalized units,
NS--nonsignificant, SDNN--standard deviation of the normal-to-normal RR
intervals duration, TP--total power under the spectral curve
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